This invention relates to an improved linear to rotary motion transmission device. More specifically, this invention relates to a simple, inexpensive device for converting a reciprocating linear input to a unidirectional rotational stepwise output. The device is particularly designed for altering the directional output of a water sprinkler nozzle.
Linear to rotary motion conversion devices in general are well known in the art and have been used in a wide variety of mechanical machinery applications for many years. One common device of this type comprises a so-called rack having a series of ratchet teeth engageable with a plurality of pawls formed on a rotatable pinion gear. Linear motion of the rack in one direction causes engagement between the ratchet teeth and the pawls to rotatably drive the pinion gear in one direction, whereas linear motion of the rack in an opposite direction causes rotational driving of the pinion gear in an opposite direction.
In many applications, it is desirable to limit conversion of a reciprocating linear input to a unidirectional rotary output. For example, in a lawn sprinkler including a sprinkler nozzle designed for full circle or 360 degree rotation, it is desirable to rotate the nozzle in a single direction of rotation using highly reliable mechanical drive components with a minimum manufacturing cost. In this regard, many prior art linear to rotary motion transmission devices have been proposed for converting linear motion to a unidirectional rotary output. However, these prior art rack and pinion devices have typically comprised relatively complicated mechanical systems requiring lateral movement of the rack out of engagement with the pinion pawls during some portion of operation. See, for example, U.S. Pat. Nos. 557,415; 662,611; 1,316,437; 3,233,472; and 3,924,476. Alternately, prior art rack and pinion systems have included relatively complicated pinion and pawl arrangements such as pivoted spring-loaded pawls, multiple pinion and ratchet combinations, and the like. See, for example, U.S. Pat. Nos. 25,550; 1,171,763; and 1,387,165.
The present invention overcomes the problems and disadvantages of the prior art by providing an improved linear to rotary motion transmission device comprising an inexpensively-formed unitary rack with ratchet teeth for engagement with flexible pawls formed integrally with an inexpensively-formed pinion for driving of the pinion in a single rotational direction.